Heaven & earth never agreed better to frame a place for
man's habitation; were it fully manured and inhabited by
industrious people. Here are mountaines, hil[l]s, plaines,
valleyes, rivers, and brookes, all running most pleasantly
into a faire Bay, compassed but for the mouth, with
fruitfull and delightsome land.
— Captain John Smith,on the Chesapeake Bay,
1606

Opening photo: Grace Brush allows graduate students
Brendan DeTemple and Joe Smith to do the heavy lifting
— or pushing — as they take a core sample at
the Blackwater National Wildlife Refuge.

Maryland's Blackwater National Wildlife Refuge, a
26,000-acre wetlands just south of Cambridge, offers the
quintessential Chesapeake Bay scene, with shallow waters,
high marsh grasses, and scattered groves of loblolly pine.
At the edge of the refuge, a modest information kiosk lists
facts about the area's muskrat, nutria, and American bald
eagle populations. A short nature drive allows visitors
glimpses of wood ducks, snow geese, great blue heron, and,
if they're lucky, the threatened eagle. To the untrained
eye, the refuge looks pristine.

Paleoecologist Grace Brush knows better. A professor in the
Whiting School of Engineering's
Department of Geography and Environmental Engineering
(DoGEE), she brings her students to Blackwater to "see
ecology first hand." As an expert on the Chesapeake Bay and
its watershed, she knows that below the water's surface are
signs of devastation. The vast meadows of underwater
grasses are gone, as are many of the bottom-dwelling
species that made their homes there. The crab and oyster
populations, so central to the Eastern Shore's character
and, once, its economy, are some of the lowest in history.
Centuries of human, or anthropogenic, influence —
deforestation, agriculture, and urbanization — have
polluted the water and starved it of oxygen. The estuary is
suffocating.

At 73, Brush has devoted 25 years of research to uncovering
the bay's past. By scrutinizing core samples of sediment
taken from areas throughout the estuary, she has been able
to show what was on the land and in the water decades,
centuries, millennia ago. More important, by reading the
history written in the sediment, she has been able to show
that the recent changes wrought by human land use are not
cyclical or temporary, but unprecedented in 14,000 years.
"It turns out," says Brush, "that the anthropogenic is
probably one of the most extensive and intensive global
disturbances that there has been."

For decades, bay managers have sought to understand how to
undo some of that damage. But to do so, they need to know
what the bay was like before Europeans arrived. Brush's
research has been invaluable to that task.

"[Brush] is one of the researchers on the bay who is always
at the cutting edge of research on practical issues," says
William C. Baker, president of the Chesapeake Bay
Foundation (CBF), a non-profit conservation organization
dedicated to saving the bay.

Adds Kim Coble, CBF Maryland executive director and senior
scientist, "Her work has given us more insight into the
impacts of our current actions than almost any other
research. It is her work that has allowed us to go well
beyond the obvious as we try to understand the problems in
the bay and seek out solutions."

This spring, Grace Brush is receiving the Mathias Medal, an
honor given by Maryland Sea Grant, Virginia Sea Grant, and
the Chesapeake Research Consortium. The medal recognizes
scientists whose lifetime contributions have not only
furthered the public's understanding of the bay but have
informed policy surrounding its management.

"Policymakers have used her work as the basis of saying
what the bay was in the past and what the bay is going to
be in the future," says Jonathan Kramer, director of
Maryland Sea Grant. "It's really very pivotal stuff."

The award, Kramer explains, has been given to the
"scientific giants" of Chesapeake Bay research. "If you
look back to her career," he adds, "as a woman in science,
she's done many things that are examples for women. She
rose through some fair adversity to become really a giant,
in this region certainly."

Brush understands the history of the Chesapeake through
the pollen preserved in its sediment. Microscopic
examination allows her to discern ragweed (top) from oak
(bottom).Photo courtesy Grace
Brush

Grace Brush is a giant who stands 5-foot-3. She's
soft-spoken and rather understated, with none of that
authoritative bluster that often comes with being a top
researcher in one's field. Though she is well-respected for
her science, her pleasant nature and genuine regard for the
people she works with seem to have created something of a
fan club.

"The most distinctive thing about Grace is what a wonderful
way she couples a fabulous personality and warm sense of
engagement with superlative science," says David R. Foster,
director of Harvard University's Harvard Forest, where
Brush spent a sabbatical year from 1995 to 1996. "There are
few scientists who have the humility and the warmth of
personality and engagement Grace does. I can't imagine
being a colleague of hers and not feeling that you were a
friend of hers."

Brush's career as a superlative scientist has somewhat
humble roots. She was turned on to paleontology as an
undergraduate at St. Francis Xavier University, when her
geology professor took the class on a field trip to look at
now-extinct tree ferns preserved in 200-million-year-old
rocks. "There were these incredible fossils," Brush says.
"And they were just beautifully preserved."

When she was 18, she landed a job as a lab technician for
the Geological Survey of Canada — her first job out
of college — near her home in Nova Scotia. (She still
lists the position on her CV.) It was 1949, and the lab was
studying mineral content in coal samples to determine which
underwater coal beds were potentially the most productive.
It was Brush's job to cut thin slices of coal for study.
When she saw tiny fossilized spores in the coal, she asked
if she could study them. She discovered that coal beds
deposited in specific geological time periods were
characterized by different assemblages of spores. By
identifying these spores, it was possible to determine
which coal beds would be worth mining.

Based on this work, the Geological Survey decided to open a
paleobotany lab and picked Brush, then 19, to be the one to
set it up. She first needed to be trained, so she enrolled
in the University of Illinois' prestigious coal research
graduate program, on a teaching assistantship. (The
Canadian government had been ready to underwrite Brush's
studies, but her father didn't want his daughter to be
beholden to the government.) After earning a master's
degree in botany, she returned to Nova Scotia for a year to
fulfill her commitment to set up the paleobotany lab. Then
she received a research assistantship in Penn State
University's renowned coal research program.

"I wouldn't have had it differently," says Brush about
juggling motherhood and scientific research. "But it wasn't
easy."

That's when life stepped in.

At Penn State, she met Lucien Brush, a bright and
fun-loving Princeton grad who was there doing graduate work
in paleontology. A year later, the two were married. What
followed were three sons — Lucien Jr., George, and
John — and several years of career stops and starts.
Grace and Lucien had agreed that he would take the best job
he could find and that she would follow, finding part-time
research opportunities wherever they went. Their route took
them to Harvard, to U.S. Geological Survey positions in
Washington, D.C., and Colorado, to the University of Iowa,
Princeton, and finally, to Johns Hopkins. (Lucien, a
professor of hydraulics and hydrology at Hopkins, died from
lung cancer in 1994.)

There were highlights for Grace: At Harvard, for instance,
where she earned a PhD in biology, she was able to work
with Elso Barghoorn, the paleontologist credited with
discovering the world's oldest fossilized organisms. He had
heard her deliver a paper on the coal work she had done in
Canada and was eager to welcome her as a student. "When I
left there," remembers Brush, Barghoorn "knew my situation,
that I was married and I was going to go wherever my
husband was. He said — and I thought at the time,
well, it's easy for you to say that — he said, 'Don't
work just for someone as a technician. Do your own work,
your own research.'"

She was able to do just that at Iowa, having obtained a
half-time position as an assistant professor of botany. "I
taught a course, got a research grant, and in a sense, that
was really ideal," she says. As part of their agreement,
Lucien would take care of the boys if she had fieldwork. "I
don't know what went on at those times," Brush says with a
laugh, "but at least he took over."

But there were also frustrations. At Princeton, though she
was given lab space, she didn't come across any other
female faculty members, students, or staff members. "I
thought, This is very strange because this is one of the
big universities in the country, one of the top
universities, and women are excluded from it," says
Brush.

Grace Brush in the lab at Harvard University, where she
earned her PhD in biology in 1956.Photo courtesy Grace
Brush

She always had to be looking for the next funding
opportunity, and throughout her early career as an
untenured researcher, she says, it was hard to be taken
seriously. It wasn't until she came to Hopkins in 1970 as a
research scientist that she began to think about pursuing
her work full time.

"I wouldn't have had it differently," she says of her
double-shift life of mother and scientist. "But it wasn't
easy."

It may not have been easy, but it may account for the fan
club. Brush, who has a habit of recounting her research
according to the graduate student working with her at the
time ("We began looking at the diatoms — Sherri
Cooper began doing that work"), understands her students as
people with full lives of their own. And she embraces them
as friends as much as colleagues. She's in touch with
students she taught 20 and 30 years ago. She goes to their
weddings. She knows their children.

"Grace and I have been close for many, many years. My
oldest daughter is named Grace," says Cecilia Lenk '76, who
worked with Brush as an undergraduate. "She's so good at
listening and she's so good at understanding people. We
were able to talk about a lot of issues" such as going to
graduate school. "She was so involved in my decision making
and my thinking about what I wanted to do in the
future."

Says Harvard's David Foster, "She's lived life as a person,
not purely a scientist. É The thing that's so impressive to
me is that being a woman and facing all the challenges
women have faced making it in the sciences, especially in
the physical sciences where she has succeeded — she
did that while simultaneously living a full life, with a
family and a husband and diverse interests. That's
extraordinary."

Things got easier for Brush when she became a tenured
professor in 1990. But she recognizes that juggling family,
life, and work is still difficult.

"I don't think she would ever come out and say she's a role
model for women, but she is — just in terms of her
doggedness, and just sticking to it no matter what
happens," says Ruth DeFries '80 (PhD), now an associate
professor at the University of Maryland. "She came to my
wedding and she stood up and gave a toast and said, 'I want
you to know that you're not just marrying this woman,
you're marrying a career.'"

"It isn't just the 20th century," says Frank Davis.
"We've been affecting the estuary for many centuries."

The Mathias Medal is named after Charles McC. Mathias, the
former U.S. senator (D-Md.) who in 1973, troubled by the
Chesapeake Bay's decline, set out to find the cause. The
project, with $27 million in funding from the Environmental
Protection Agency, would eventually become the Chesapeake
Bay Program.

By the early '70s, it was clear that the bay was in
trouble, suffering what Brush has called a "near crash of
the system." A major indicator of that crash was the
disappearance — in fact, the extinction in some areas
— of underwater grasses known as submerged
macrophytes. Scientists and policymakers began asking the
same kinds of questions about the disappearance of the
grasses as they do today about global warming: Is this the
result of human activity, or simply part of a natural
cycle? And if humans are to blame, what specifically are we
doing wrong?

Brush had been attending the Chesapeake Bay Program
meetings and, in 1978, made a proposal to study the
submerged macrophytes using a technique she had employed
previously in the bay. In that earlier study, she used core
samples taken from Baltimore's Back River to show that when
a sewage treatment plant went on line by the river, the
underwater grasses died off.

"When the Chesapeake Bay Program began," says Brush, "they
were asking these very large questions. That's when I
thought, We can probably answer some of those questions."

The basis for Brush's bay research is the mud found at the
bottom of the bay and at its edges. As silt and clay
particles settle, they bury and preserve chemicals and
organisms, creating a record of the climate, the plant and
animal life, and the water quality at the time they were
deposited. By analyzing core samples of the sediment, Brush
can reconstruct that history. As a settling basin,
Chesapeake Bay proved perfect for this kind of work —
Brush would eventually find undisturbed cores that date
back 14,000 years.

"Things that were happening on the land were being recorded
very, very accurately," says Brush. "I didn't expect to
find it as precisely recorded."

To collect cores, Brush uses a clear plastic tube fixed
with a piston at the bottom and attached to a longer metal
pole. The pole works as a handle to force the tube into the
sediment; as the tube is submerged, the piston is pushed up
inside the tube, creating a vacuum. When the tube is
removed from the sediment, it brings with it a perfect
cylinder of clay and detritus.

Brush then dates the cores using a combination of carbon-14
analysis and what she calls "pollen horizons." For example,
since ragweed flourishes in recently tilled land, a jump in
ragweed pollen in the sediment indicates European
settlement, when the land was cleared for farming. A sudden
disappearance of chestnut pollen indicates the 1920s and
early '30s, when disease wiped out these trees in the
region. Using these pollen horizons, Brush then can assign
dates to smaller increments within the core sample. By
looking at what lived and died along that timeline, she is
able to compare pre- and post-European conditions.

Since the time of European settlement, major deforestation
on the land has caused increased sedimentation in the
water, explains Brush. That extra silt muddies the bay,
preventing light from reaching the bottom and killing off
the plants and animals that live there. The fertilizers
used in farming (first guano and later chemicals), plus the
treated sewage that comes with a growing population, have
increased the amount of nutrients, especially nitrogen and
phosphorous, flowing into the bay. Those nutrients cause
algae blooms, which increase turbidity and, when the algae
die and decay, deplete oxygen in the water, a condition
called anoxia.

Brush, here with grad student Mason Thronburg, works at
the edge of the Gwynns Falls, where it flows into Baltimore's
Inner Harbor.

When Brush examines a core, she can see when species appear
and when they die out. By studying diatoms, which are tiny
algae whose skeletons are well-preserved in sediment, she
can see when the bottom-dwelling, or benthic, species were
replaced by those that live in the upper part of the water,
or planktonic species — an indication of extensive
anoxia. And she has found that, though there were cycles of
rise and decline before Europeans settled here, there has
never been the kind of sustained loss of species that the
bay has experienced since then.

"What she showed," says Frank W. Davis '82 (PhD), who as a
graduate student worked on Brush's submerged macrophyte
study, "was this strong coupling between what we're doing
on the land and what's happening in the estuary. And that
it isn't just the 20th century — we've been affecting
the estuary for many centuries."

The loss of the grasses, Brush was able to show, was not
natural; it was manmade. Says Davis, now a professor at the
University of California, Santa Barbara, "We were able to
look back through the sediment record and see that over 500
or 600 years, that disappearance of some species from the
upper Chesapeake Bay was unprecedented."

Hurricane Agnes devastated the region in 1972. "There was a
lot of controversy," says Brush. "People were arguing about
what causes anoxia — is it the amount of sediment and
nutrients coming into the bay, or is it the amount of
rainfall? And it was pretty clear with this record that,
sure the rainfall is going to affect things, but we had
varying rainfalls before [European] settlement, and we
didn't have this very extensive anoxic condition."

Though industrial plants were suspect, Brush showed that
widespread deforestation and agriculture were as much, if
not more, to blame. "Out of that first work," says Brush,
"we were able to show the effect of agriculture — the
very high sedimentation rates — and the effect of
those sedimentation rates on the submerged grasses."

Says CBF's Will Baker, "It really put an end to all the
talk at the time that this was nothing to worry about, just
a natural cycle."

Brush and DeTemple make their way through the
marsh.

Over the past decades, Brush has collected hundreds of
cores, answering specific questions that together tell an
ever more complete story of the bay. She is co-editor, with
the Krieger School of Arts and Sciences' Philip D. Curtin
and George W. Fisher, of Discovering the Chesapeake: The
History of an Ecosystem. And she has authored dozens of
studies — often with her students — about the
Chesapeake Bay that have appeared in journals including
Science, Estuaries, and Environmental Reviews.

For instance, Sherri Cooper and Brush used diatoms to prove
that agriculture increases anoxia. Bill Hilgartner, Humaira
Khan, and Brush were able to determine when fresh water
marshes originated and to show how vital they are in
protecting the bay from nutrient loading. Another student,
Angie Arnold, worked with Brush to determine that a certain
species of worms, which were bottom-feeders, were once as
abundant in the bay as filter-feeders like oysters,
prompting new questions about what restoration should mean
in the bay. And Emily Elliott is working with Brush on a
study that uses isotopes to identify specific sources of
nitrogen.

"Unfortunately we don't seem to be looking for anything
good happening," says Brush. "We would be so utterly
surprised if we found a core with benthic diatoms in the
top sediments! That would be a sign that we've got clear
water!"

That seems a long way off. Though there is some dispute
about the progress the Chesapeake has made over the past 30
years, no one would claim that the bay is healthy. (In its
most recent "State of the Bay" report, the Chesapeake Bay
Foundation gave the bay 27 points out of 100 — 100
being the bay Captain John Smith found in the early 17th
century.) Brush, like so many bay scientists, would like to
see the bay restored to its former abundance. Though she
doesn't actively participate in the policy and the politics
surrounding the bay, she has made a life's work of
providing vital information to the people who do. Says
Brush, "I think the way we are most effective is by getting
really indisputable evidence to the people whose job it is
to argue for the right management and policy."

Her work is paying off, as evidenced by the Mathias Medal,
as well as her considerable reputation among the Chesapeake
Bay community.

"Dr. Brush and [the bay scientific community] give us the
credibility as a society to determine what policies are
needed to improve the environment," says Baker. "That's the
importance. The scientists have really analyzed and
determined what the problem is and how to fix it —
and that's no small feat."

Brush says she is motivated by the possibility of making
the bay's "very dramatic history" more and more complete.
Though the Chesapeake itself seems to give her a certain
inspiration.

"Every time I drive across the Chesapeake Bay Bridge, I
just think how beautiful the bay is," says Brush. "Its
beauty has remained, despite everything that's gone."